Some rugby fans could miss out on a good slice of the action at Eden Park in next year's World Cup after the $256 million upgrade left about 100 seats without full views of the pitch.

Fans who buy the seats, in the south western section of the new South Stand, will not be able to see almost all of one try line and a good chunk of the field.

Rugby NZ 2011 spokesman Mike Jaspers said none of the seats had been sold so far in either phase one or phase two of ticketing for the World Cup.

"If we were to sell them it would be made clear that they are sight-restricted," Jaspers said.

"It's not uncommon for any venue to have seats that are restricted."

He said the seats may be used for other purposes, such as broadcasting.

Eden Park Trust chairman John Waller told the New Zealand Herald yesterday he knew of the issue, and assured fans that no one would have an impeded view.

Mr Waller said the stadium had been designed with the possibility that the West Stand might be demolished, although there were no plans for that to happen.

"If you go right up on the edge of the South Stand, at the west end you can't see a bit of one corner of the paddock," he said.

"We've known ... that's why they're not included in seat counts for Rugby World Cup," he said

Wellington's waterfront "Cake Tin" stadium has no seats with obstructed views.